KR100648386B1 - Recovering method of aluminium metal from Waste Aluminium Can - Google Patents

Abstract

The present invention relates to a method of recovering metallic aluminum from waste aluminum cans by casting molten aluminum pieces which have undergone the process of sorting, pulverizing and removing organic matter in an aluminum melting furnace and then casting them into aluminum ingots. The molten aluminum is introduced into the molten chamber so that the aluminum melt forms a vortex in the molten chamber. The waste aluminum scrap crushed to a size of 2 to 15 mm into the molten aluminum melt is introduced into the molten chamber, and then cast into an aluminum ingot, thereby casting metal from the waste aluminum can. A method for recovering aluminum.

The method of the present invention has the effect of recovering the metal aluminum with a high recovery rate from the waste aluminum can.

Waste aluminum cans, regeneration treatment, vortex melts, aluminum ingots

Description

Recovering method of aluminum metal from Waste Aluminum Can}

1 is a process diagram schematically showing the process of the present invention.

FIG. 2 is a cross-sectional view of an aluminum melting furnace which swirls aluminum molten metal in the present invention and injects aluminum into the swirl to melt it.

-Explanation of symbols for the main parts of the drawings-

1: aluminum melting device

2: Melting chamber

3: Charge well

4: vortex molten metal

5: reflection furnace

6: pump

7: tapping pipe

8: Feeding device

9: aluminum melt

10, 11: gas outlet

The present invention relates to a method for recovering metallic aluminum from waste aluminum cans.

Aluminum (Al) is lightweight, has good corrosion resistance, processability, high electrical and heat conductivity, and beautiful color, so it is not only used for household goods such as refrigerators and washing machines, but also for automobiles and aircrafts. Extensive and sometimes used as a deoxidizer in steel smelting. Since aluminum is an expensive metal, aluminum products discarded after use are recovered and recycled.

Recycling waste aluminum products is a very useful task in terms of preventing environmental pollution as well as economic benefits of recycling waste.

Republic of Korea Patent Publication No. 10-0232863 (Registration date 1999.9.8.) To decompose the organic material attached to the aluminum surface, such as deposits, paints by heating the aluminum scrap to 480 ~ 530 ℃ and cooled to 100 ℃ or less After removing the oxide produced by crushing with an impact crusher, remove the subdivision of 10mm or less and press the aluminum scrap made from the press molded body with the maximum weight of 7Kg and the specific gravity of 2.4 ~ 2.65 and the volume / surface ratio of the molded body at least 1.85 by reflection. Disclosed is a method for recovering to metallic aluminum by treating with.

Republic of Korea Patent Publication No. 10-0227317 (Registration date 1999.8.2) is to carbonize the combustibles of the metal aluminum-containing material in the furnace of the oxygen concentration of less than 10% by volume and the temperature range of 300 ~ 600 ℃ Disclosed is a method for recovering aluminum from a metal aluminum-containing material that is sieved after cooling or used to separate carbides using a magnet.

In addition, aluminum recovered from aluminum waste is sorted by removing impurities, and then melted into aluminum ingots, which are supplied as raw materials for various aluminum products.

In the method of recovering aluminum from the waste aluminum can, the recovered aluminum is placed in an aluminum melting furnace such as a reflection furnace or a crucible furnace, heated to about 700 ° C., and then cooled to form aluminum ingots.

However, in the method of melting the waste aluminum cans and recovering them into aluminum ingots, the waste aluminum cans are brought into contact with air for a considerable time before being heated. The heated aluminum can be easily oxidized in the air. If the contact time is longer, the loss due to oxidation of aluminum is increased, the recovery rate is lowered, there is a problem that the recovery rate is lower than 70%.

In addition, as foreign substances such as moisture and paint remaining on the surface of the aluminum can are gasified, it generates gases such as NOx and SOx, and these react with aluminum together with oxygen in the air to make aluminum dross. It may adversely affect.

Therefore, in this field, there is a need to develop a method for reclaiming waste aluminum that can increase the recovery rate of aluminum.

An object of the present invention is to provide a method for recovering metal aluminum from waste aluminum cans with high recovery rate.

The present inventors carbonize the combustible material adhered to the surface by crushing the waste aluminum can and cutting the aluminum can pieces cut to 30-100mm size to a temperature lower than the melting point of aluminum (660 ° C), and cooling them to 2-15mm. In the metal aluminum recovery method, which is crushed to a size and melted in an aluminum smelter such as a reflector, and recovered as an aluminum ingot, when molten aluminum pieces of 2 to 15 mm are melted in an aluminum smelter, heat-melted aluminum in an aluminum smelter such as a reflector The solution is pressurized by a pump and flowed into a separate cylindrical melt chamber so that the aluminum melt rotates through the cylindrical wall of the melt polymer, causing vortices. The aluminum is crushed into a size of 2 to 15 mm in the aluminum vortex melt causing the vortex. When the piece is melted, the injected piece of aluminum is used for vortexing aluminum. The present invention was completed by confirming that the sucked into the hot water melted to shorten the contact time between the aluminum pieces and the air, thereby reducing the amount of aluminum lost during the melting process, thereby increasing the recovery rate of the aluminum.

The present invention relates to a method for recovering aluminum in high yield from waste aluminum cans.

The present invention is a process for disassembling the pressurized aluminum can into a single can state with an impact disassembly, and removing wastes such as iron, vinyl, and soil from the dismantled waste aluminum cans, and sorting only waste aluminum cans. Cutting the waste aluminum cans sorted by 30 ~ 100mm and cutting the waste aluminum cans into a rotary reactor by using a hot gas supplied from a hot air generator or by direct heating with a burner flame. And burning the organic materials such as paints and remaining drinks attached to the surface of the waste aluminum products cut by heating at a temperature ranging from 400 to 750 ° C. lower than the aluminum melting temperature. And burning residues are separated and sorted, and at the same time, they are shredded to particles of 2 to 15 mm Process and that; It is composed of a process of forcibly generating molten vortex phenomenon (Vortex) in the molten aluminum molten liquid in the reflection furnace and injecting and dissolving the granulated waste aluminum can pulverized into the vortex melt, and then manufacturing the aluminum ingot by a casting machine.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a process diagram schematically showing a process of the present invention, which will be described in detail as follows.

First, the waste aluminum can press molded body distributed in the form of press-molded product is dismantled into a single can state by an impact breaker.

The aluminum can press molded body refers to a molded body whose volume is reduced by pressing the recovered aluminum cans as described in Korean Patent Publication No. 10-0232863.

Subsequently, the waste aluminum can product, which is dismantled in a single can state, is transferred to a separator through a conveying mechanism such as a roller conveyor, and the iron is removed from the waste can collection and distribution process using an electromagnet. The back is removed using the difference in specific gravity and the Eddy Current to the magnetic force to sort only waste aluminum cans.

The sorted waste aluminum can product is cut into cutters of 30 ~ 100mm using a cutter or shredder to increase the area where organic materials and paints attached to the surface of waste aluminum cans come into contact with the hot gas for combustion.

The sorted / cut waste aluminum cans are fed into a rotary kiln through a transfer mechanism such as a roller conveyor and heated with hot gas supplied from a hot gas generator, or directly heated with burner flames. It burns material and paint.

Hot gas generator (Hot gas generator) is a device that supplies the heated air by heating the air to 400 ~ 750 ℃ with a burner flame.

The organic material combustion process maintains the ambient temperature of the rotary reactor inlet at 400-750 ° C. lower than the aluminum melting temperature in order to heat-burn only the organic material attached to the surface by hot gas without melting the waste aluminum product. Maintaining the temperature of the rotary reactor inlet in the above temperature range is made by receiving a hot gas produced from a hot gas supplier that burns fuel to produce a hot gas, or by direct heating by a burner flame. When the cut waste aluminum product is supplied in the direction to be fed into the rotary reactor, it instantly removes high-molecular organic materials such as paints attached to the waste aluminum product surface without melting aluminum.

In the process, the inside of the rotary reactor is maintained in a temperature range lower than the aluminum melting temperature (660 ℃) and the outlet temperature is maintained at about 350 ~ 600 ℃. Controlling the outlet temperature in the above range is to prevent the aluminum melting temperature from reaching even if the temperature inside the reactor rises due to the combustion of paint or synthetic resin attached to the surface of the waste aluminum can.

In addition, the hot gas supplied to perform the process is supplied by adjusting the oxygen concentration in the hot gas generator (Hot Gas Generator) so that the oxygen concentration in the exhaust gas is about 6 ~ 8% by volume, the general air through a forced blower Is supplied to a hot gas generator to control the oxygen concentration in the exhaust gas. Controlling the oxygen concentration in the above range means that if too much oxygen is supplied, all of the combustibles attached to the surface of the waste aluminum product are burned in an instant, and the temperature in the rotary reactor rises rapidly, so that the temperature of the rotary reactor is not controlled and is caused by excess oxygen. This is because the oxidation reaction of aluminum is the cause of the final reduction in recovery, while in the case of a small amount of the organic material removal effect due to combustion is insufficient so that the organic material is gradually burned completely.

In addition, the internal pressure of the rotary reactor in the process is maintained below 5mmHg and rotated at a speed of 5 ~ 8rpm to properly treat the waste aluminum can product. By rotating the rotary reactor to the above speed range, the waste aluminum product is properly stirred inside the rotary reactor to effectively burn the organic matter attached to the surface, and the residence time of the waste aluminum product is 20-40 minutes. do.

After discharging the waste aluminum product (Flake) from which the organic matter attached to the surface of the waste aluminum is removed to the cooling chamber through the above process, the waste aluminum product from which the organic material is removed is cooled to 70-200 ° C. in the cooler. Is cooled. The cooling of the waste aluminum product in the above temperature range is to prevent heat from being generated during the grinding in the grinder, thereby overheating the bearing part of the grinder, or melting and fusion of aluminum in the grinder of aluminum due to the grinding heat.

The aluminum put into the grinder is finely pulverized into granules with a particle diameter of 2 ~ 15mm, and then conveyed to the powder by a fan. The combustion residues such as dust and oxides are sorted by centrifugal force cyclone, It is transported to the storage hopper while removing the back, and the pulverized products of waste aluminum products from which combustion residue and dust are removed are stored in the granule. Grinding the waste aluminum product to 2 ~ 15mm is excessively fine grinding, the loss rate is high and there is a risk of explosion, if too large it is difficult to reduce the specific gravity during molding is controlled in the above range.

The waste aluminum products in the storage tank are again conveyed to the press by means of a conveying mechanism such as a conveyor and manufactured into cylindrical type aluminum ingots or aluminum granules, or the airtightness of the furnace is controlled to control the oxygen concentration. It is made of aluminum ingot after being put into the furnace in the shape of the retained reflection furnace and melting.

As described above, the aluminum ingot manufactured from the waste aluminum can can produce aluminum ingots with a purity of 96% to 97%, and may be in the form of granules or ingots depending on the application process.

In the present invention, the aluminum can (Flake) or the pulverized aluminum can (Granule) from which the paint and organic material treated in the rotary reactor are removed is vortex melt phenomenon in a separate melting material charge (Charge well) in the reflection furnace (Vortexer) is forcibly generated and settled in the molten metal by the vortex generated to dissolve it.

At this time, the purpose of dissolving by submerging the melted material into the melt vortex can be dissolved by excluding the oxide oxide caused by the burner directing of the reflection furnace, and the dissolution efficiency of the melted material is increased so that the dissolution efficiency is relatively increased. In addition, it is possible to obtain ancillary effects such as a decrease in the amount of flux used and a reduction in the processing capacity of the dust collector.

The reason for dissolving aluminum using the vortex melt in the present invention is as follows.

In general, the collected waste aluminum cans are melted in an aluminum melting furnace to produce metal aluminum ingots.

Therefore, the aluminum melting process cannot be carried out in a vacuum or anoxic state, and aluminum easily reacts with oxygen at a high temperature near the melting point to form aluminum oxide, so that the recovery rate is recovered to metallic aluminum when the contact time with oxygen at a high temperature becomes long. Will fall.

However, if the aluminum is melted by injecting it into the aluminum vortex melt, the aluminum vortex is a high-speed aluminum melt flowing at a high speed, so that the heat capacity per unit volume increases, so that the heat exchange between the solid aluminum and the liquid aluminum occurs quickly. The dissolution rate is faster.

When the aluminum melt pressurized using a pump is introduced into a cylindrical chamber of a certain size, the aluminum melt rotates through the vessel wall, causing vortices, and when aluminum pieces are put into the aluminum vortex melt causing this vortex, The silver is quickly sucked into the aluminum melt and heat exchange occurs to melt it.

As a result, the reaction time with oxygen is reduced, and the generation of the combustion products due to the oxidation reaction is reduced, so the processing capacity of the dust collector, which is an environmental facility, is also reduced, and the amount of aluminum dross generated is also reduced, thereby reducing the aluminum in the aluminum dross. This has the advantage that the amount of flux used to recover is also reduced.

Hereinafter, the present invention will be described in detail with reference to Examples.

Example 1

According to the process shown in FIG. 1, the waste aluminum cans were recovered by aluminum ingot in the aluminum melting apparatus shown in FIG.

After dismantling the waste aluminum can product formed by press molding of 1,000Kg per hour in the form of a single can, iron and glass and plastic were separated and separated by a separator, and the cut aluminum can product was cut to about 50mm and put into a rotary reactor. The hot gas generated at the hot gas generator at 630 ° C. was supplied to the rotary reactor to heat and remove the organic material attached to the surface of the waste aluminum product. The aluminum strip from which the organic material was removed was cooled to about 80 ° C., and then ground to a particle diameter of about 10 mm using a grinder. This aluminum pulverized product was formed in a vortex (4) formed in the lower portion of the crash well (3) of the melting chamber (2) by a fixed-quantity continuous feeder (8) such as a screw conveyor. After the continuous injection into the precipitate was settled (Submerge) and melted, it was molded into a casting machine and cast into an aluminum ingot. The recovered aluminum ingot was 870 Kg per hour (87% recovery) and the aluminum purity was 97.12%.

The aluminum melting apparatus 1 is as shown in FIG. 2, 5 is a reflection path. Here, separately prepared aluminum is melted to prepare an aluminum melt. (6) is a pump for conveying aluminum melt. When the aluminum melt is pressurized and supplied to the feeder using this pump, a vortex of aluminum melt is formed in the cylindrical melt chamber formed under the feeder. In this embodiment, in order to form the vortex molten metal 4, the molten aluminum feed pipe having an inner diameter of 4 kPa was introduced into the molten chamber 2 having a diameter of 60 cm at a flow rate of 1 m / sec. The molten aluminum melt is supplied to the reflection furnace 5 through the tapping pipe 7. The aluminum ingot can be obtained by taking out and casting the aluminum melt 9 in the reflection furnace. In Fig. 2, (10) and (11) are gas outlets, and the " → " table shows the conveying direction of the aluminum melt.

Example 2

The waste aluminum can product of 1,000Kg per hour was dismantled into single cans, and then iron and glass and plastic were separated and separated by a sorting machine. The cut aluminum can product was cut to about 50 mm and put into a rotary reactor. The hot gas generated from the hot gas generator is supplied to the rotary reactor to heat and remove the organic material attached to the surface of the waste aluminum product at a temperature of about 630 ° C., and then the waste aluminum can from which the organic material is removed is transferred to the cooler and cooled to about 150 ° C. Afterwards, it is transferred to a grinder and crushed to a size of about 5 mm and then transferred to a fan. After dust and oxide are removed by centrifugal cyclones, they are transferred to a storage tank and stored. The melted material was continuously poured into a vortex (Vortex), precipitated (Submerge), melted, cast, and manufactured into an aluminum ingot. The recovered aluminum ingot was 880 kg per hour (88% recovery) and the aluminum purity was 97.12%. The method of forming the vortex melt is the same as in Example 1.

Comparative example

The waste aluminum can product of 1,000Kg per hour was dismantled into single cans, and then iron and glass and plastic were separated and separated by a sorting machine. The cut aluminum can product was cut to about 50 mm and put into a rotary reactor. The hot gas generated from the hot gas generator is supplied to the rotary reactor to heat and remove the organic material attached to the surface of the waste aluminum product at a temperature of about 630 ° C., and then the waste aluminum can from which the organic material is removed is transferred to the cooler and cooled to about 150 ° C. After that, it is transferred to a grinder and crushed to a size of about 5 mm and then transferred to a fan, and dust and oxide are removed by a centrifugal cyclone, and then transferred to a storage tank and stored therein. Furnace (5) was maintained at 720 ℃ melt and then cast in a caster to produce an aluminum ingot. The obtained aluminum ingot was 650 Kg / Hr with a recovery of 65% and an aluminum purity of 96.45%.

According to the method of the present invention, the aluminum recovery rate is improved to 87 to 88% or more at 70% or less, and the obtained aluminum purity is also improved to 96 to 97%. Significantly reduced fuel consumption led to a reduction in CO ₂ gas emissions.

The method of the present invention has the effect of recovering the metal aluminum with a high recovery rate from the waste aluminum can.

Claims (1)

A method of recovering metallic aluminum from a waste aluminum can by casting molten aluminum scrap, which has undergone sorting, pulverization and organic matter removal, by heating and melting in an aluminum melting furnace, into a cylindrical molten chamber by pressurizing the heated molten aluminum melt with a pump. The aluminum melt is introduced to form a vortex in the molten chamber. The waste aluminum scrap crushed to a size of 2 to 15 mm is introduced into the molten aluminum melt, which is then melted and cast into an aluminum ingot to recover the metal aluminum from the waste aluminum can. How to.

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